Packaging signals for phage P22 on the chromosome of Salmonella typhimurium.

Numbers of transducing particles for a set of 28 different chromosomal markers were determined in a lysate of Salmonella phage P22. The results were plotted with regard to the map positions of the transduced loci. Maxima of the resulting curve are interpreted as positions of start signals ("pac-sites") for packaging series on the Salmonella chromosome. 5-6 pac-sites could be found as a minimum estimate.